DONALD Trump has said chief of staff John Kelly will leave his job by the year’s end amid an expected West Wing reshuffling.

It reflects a focus on the US president’s 2020 re-election campaign and the challenge of governing with Democrats reclaiming control in the House.

An announcement about Kelly’s replacement is expected in the coming days, the president confirmed.

Nick Ayers, Vice-President Mike Pence’s chief of staff, is Trump’s top choice to replace Kelly and the two have held talks for months about the job, a White House official said.

Trump and Ayers are working out specifics terms under which Ayers would fill the role and the time commitment he will make, the official said. Trump wants his next chief of staff to agree to hold the job through the 2020 election.

Ayers, who has young triplets, had long planned to leave the administration at the end of the year.

The official spoke on the condition of anonymity to discuss sensitive personnel matters.

The announcement came a day after Trump named his picks for attorney general and ambassador to the United Nations, and two senior aides shifted from the White House to Trump’s campaign.

Kelly had been credited with imposing order on a chaotic West Wing after his arrival in June 2017 from his post as homeland security secretary. His iron fist also alienated some long-time Trump allies and he grew increasingly isolated, with a greatly diminished role.

Known through the West Wing as “the chief” or “the general”, the retired Marine Corps four-star general was tapped by Trump via a tweet to try to normalise a White House riven by infighting.

“John Kelly will leaving – I don’t know if I can say retiring – but he’s a great guy,” Trump told reporters.

Kelly had early successes, including ending an open-door Oval Office policy and instituting a more rigorous policy process to try to prevent staffers from going directly to Trump. But those efforts also miffed the president and some of his most influential outside allies, who had grown accustomed to unimpeded access.

Kelly’s handling of domestic violence accusations against the former White House staff secretary also caused consternation, especially among lower-level White House staffers, who believed he had lied to them about when he found out about the allegations.

Ayers, 36, would be the youngest chief of staff since 34-year-old Hamilton Jordan served under Jimmy Carter.